<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
        <div id="example">
            <div>
                <input v-model="parentMsg">
                <br>
                <child v-bind:my-message="parentMsg"></child>
            </div>
        </div>

        <script src="https://cdn.staticfile.org/vue/2.2.6/vue.js"></script>
        <script>
            Vue.component('child', {
                // camelCase in JavaScript
                props: ['myMessage'],
                template: '<span>{{ myMessage }}</span>'
            });

            var vm = new Vue({
                el: "#example",
                data: {
                    "parentMsg": ""
                },
                methods: {},
                components: {}
            });
        </script>
    </body>
</html>